Belt conveyors are used to transport material from one location to another. For example, belt conveyors can transport material such as gravel, sand, rock, grain, etc. A belt conveyor typically has a number of pulleys for support, as well as a drive pulley to move the conveyor. The drive pulley is typically the head pulley. A tail pulley is located at the other end of the conveyor. The material travels on top of the conveyor from the tail pulley to the head pulley.
Material falls off of the top of the conveyor and onto the bottom of the conveyor belt (which moves from the head pulley to the tail pulley). The material thus becomes located between the tail pulley and the belt conveyor.
If a drum pulley is used, the material can cause damage to the belt and to the pulley. Also the material will cause the belt to lose tracking with the pulley. Tracking is side-to-side alignment of the belt on a pulley. A belt that loses tracking moves to one side or the other on the pulley. Loss of tracking can damage the belt and reduce the load carrying capacity of the belt.
Consequently, wing pulleys are used in such material handling conveyors as the tail pulleys. A wing pulley has wings that extend radially outwardly; the wings contact the belt and act as standoffs. Material on the belt locates between the wings and is not compressed between the belt and the pulley. Thus, damage to the belt and the pulley by the material is minimized. Furthermore, by using a wing pulley, better belt tracking on the pulley is achieved.
Wing pulleys have a number of attributes, including material ejection. Once material enters the spaces between the wings, it is desirable to move that material out of the pulley as soon as possible to avoid material building up or compacting within the pulley, essentially loading the pulley with material. Another attribute is belt tracking; the belt should stay aligned on the pulley regardless of the material entering and ejecting from the pulley.
It is desirable to provide a wing pulley that operates in a satisfactory manner.